Building Electronics Gadgets

[Stiganator]

I've decided to take up the fine art of garage electronics tinkering. I'd like to be able to make some simple PCBs down to about 1mm traces and do some surface mounting of LQFP ICs. I ordered some free samples from Texas Instruments. Looking through their catalog I never realized how many different ICs and components there are. I know the basics of RC Op-Amp stuff, but how do you know what the heck all these things do and when you need them?

Is there some electronics bible, I am unaware of? What types of courses might a University teach on the subject of what I would call higher order circuits/device design.

Any feedback is welcome.

 

[BrownTown]

Well all the devices have datasheets that should tell you what all they can do. As for advanced circuit design, I know at my university there is no course that does what you want in terms of actually teaching you have to create an entier system. However if you just read the datasheets carefully and know alot of the basics you should be fine. I know like for exammple at first I was thinking it would take some absurd circuit i would have to design to produce a stable +5V, but for pretty much anything like that there is some IC already desisgned that will do exactly what you want, its all just matching them up right based on the datasheets and stuff. Like if something says it can only source 200mA then make sure to read the datasheet for the device its driving to make sure it never draws more than that etc.

 

[Stiganator]

What about PCB software I read review of lots of them. What do you use for something up to the complexity of an mp3 player or something of that nature?

Where do you buy blank PCB boards? I'm thinking of making a UV etching chamber.

 

[BrownTown]

Originally posted by: Stiganator
What about PCB software I read review of lots of them. What do you use for something up to the complexity of an mp3 player or something of that nature?

Where do you buy blank PCB boards? I'm thinking of making a UV etching chamber.

Well making your own etching chamber is pretty over the top, there are a dozen sites on the internet where you can just send them the CAD file and they will fabricate a board for you, no reason to bother with all the extra work, extra money and dangerous chemicals and ending up with a worse product in the end to boot.

EDIT: so I looked it up and there are alot of people on he internets who ahve done the same thing and have made sites that can guide you. You should be able to solder by hand using just a normal iron to a PCB you design with the rest of the circuitry. This is the site I used to make the PCB for my project

 

[CycloWizard]

Like BT said, you just have to fish through the supplier's catalog/website/datasheets to find the IC that does what you want. I always let someone else worry about that part, since experience can save you a lot of time thumbing through a catalog. There are a few people that post here fairly regularly that etch their own PCB. I use a program called ExpressPCB. It's more pricey than doing it yourself, but time is money for what I'm doing. I draw the multi-layered layout in the free program, then simply click the submit button and they mail me the PCB within a couple days. It's been a while since I ordered any, but IIRC, it's like $60 for two copies of your board.

 

[BrownTown]

Originally posted by: CycloWizard
It's been a while since I ordered any, but IIRC, it's like $60 for two copies of your board.

It was $160 for 4 of these. Nothing complicated, there was a 4x7 inch mount already determined, so there wasn't any need to try and make anything small, plus the big parts on the right are all 120V power supply stuff, so like that transformer and such are big things with only a few pins.

 

[PottedMeat]

I make my own 2-sided PCBs, never used a service before. Basically I go through the process shown here:

http://www.mgchemicals.com/dow...edia/photofablarge.wmv

1. Make the circuit using EAGLE - you can make custom parts from your data sheets.
2. Print it out on laser transparencies - I've gotten good results with MG chemicals branded stuff.
3. Cut out a rough size PCB.
4. Using a paper copy of the circuit, drill a hole or two as a guide to place the transparency.
5. Using a kitchen timer, expose each side to a fluorescent lamp ( ~6" away from the tube ), for about 5-8 minutes.
6. Develop the PCB in the sodium hydroxide solution soon afterwards.
7. Warm the ferric chloride bottle in a container of hot water.
8. Suspend the PCB with a piece of insulated wire in the ferric chloride, checking every ~3-5 minutes.

Everything should be done in glass or chemical/heat resistant containers.

Things that will make the process go more smoothly/easier:
Drill Press
Magnetic Stirrer
Band Saw

You will need small drill bits - you can get random packs of 20 from harbor freight for ~5 bucks.

 

[BrownTown]

I dunno man, I have heard some bad stuff about FeCl, maybe if I had my own fume hood it would be all good, but for most people I think it makes sense just to order boards online. You can get 2 boards for $100 and no hassle. I can't imagine having to drill out all those tiny holes, plus they won't be plated through so the solder won't flow all around the pins and stuff. I guess maybe if you want to be really DIY then thats the way to go, but by that point I feal your just making alot of extra work for yourself (but if its all for entertainment anyways then why not I guess).

 

[wwswimming]

Originally posted by: Stiganator
I've decided to take up the fine art of garage electronics tinkering. I'd like to be able to make some simple PCBs down to about 1mm traces and do some surface mounting of LQFP ICs. I ordered some free samples from Texas Instruments. Looking through their catalog I never realized how many different ICs and components there are. I know the basics of RC Op-Amp stuff, but how do you know what the heck all these things do and when you need them?

e.g. if you're shopping in the Linear Tech databook
http://www.linear.com/
& see something you like & persuade them to send you a free sample. it might
come in various packages. if you can find an applications engineer to help you,
they'll tell you which one has the least fine pitch IC leads (IC leads spread further
apart).

Is there some electronics bible, I am unaware of? What types of courses might a University teach on the subject of what I would call higher order circuits/device design.

http://www.microe.rit.edu/abetreport.php?page=13
@ Rensellear, i think.

State Univ. New York @ Buffalo
http://www.packaging.buffalo.edu/

Charles Harper, had a book on Electronics Packaging in the early '80's.
http://www.amazon.com/Electron...-Charles/dp/0071430482

and it's still around !

if you can get into an IEEE/ ISHM (inter. society of hybrid micro-circuits - if it's still around) session or related trade show, that's a good learning place.

there used to be a magazine called "electronics packaging & production". best i could do for right now
http://www2.electronicproducts.com/

Global SMT & Packaging, another magazine or book of ads about packaging with a few articles
http://www.globalsmt.net/

another expensive book, semi-comprehensive
http://www.amazon.com/Electron...iability/dp/0070371350

another packaging handbook, part of it online
http://www.engnetbase.com/ejou...ary/summary.asp?id=412

and another packaging handbook
http://www.calce.umd.edu/gener...iptions/materials.html

Wiki overview, but it could really use some pictures
http://en.wikipedia.org/wiki/I...ated_circuit_packaging

you can do 1 mm (.040 traces & spaces ?) using an exacto knife, cutting the copper foil
& peeling it back with tweezers.

or put tape down on the board, cut away some of the tape. if you place the resulting
partially taped circuit board in an acid etchant bath (following all safety precautions),
rinse it off etc., you'll get an etched board.

normally i wouldn't suggest it but ... i saw this done by a co-worker in the microwave
lab at Wiltron/Anritsu in the '80's, for a multi-port pin switch. he then assembled the
circuit & tested it in a scalar network analyzer, having printed out predicted performance
on a piece of clear plastic & taped it on top of the display. 99% mapping between
predicted & measured performance, with frequency on the horiz. axis & amplitude
on the vertical axis. he had about 30 years hands-on experience. one of those
do-not-try-this-at-home, at least not without good ventilation & safety glasses type
projects.

 

[PottedMeat]

Originally posted by: BrownTown
I dunno man, I have heard some bad stuff about FeCl, maybe if I had my own fume hood it would be all good, but for most people I think it makes sense just to order boards online. You can get 2 boards for $100 and no hassle. I can't imagine having to drill out all those tiny holes, plus they won't be plated through so the solder won't flow all around the pins and stuff. I guess maybe if you want to be really DIY then thats the way to go, but by that point I feal your just making alot of extra work for yourself (but if its all for entertainment anyways then why not I guess).

Yeah it can be a lot of trouble - broken bits, bad traces, undissolved copper bridges, etc. I don't really worry about the fumes, - all done in the garage with open doors. In the end though it probably is more expensive, I guess I just go all out DIY heh.

 

[bobsmith1492]

Get some of the "100-in-one" "300-in-one" kits from Radio Shack and go through the projects, if they still sell these. I taught myself in elementary school with those things. You can get a lot of electronic circuit concepts by example just by building the projects. Their old "Analog circuits" and "Digital circuits" books were useful, too.

Breadboards are the way to go for tinkering - no need to worry about soldering or rework. Save the PCBs for final products and order them from somewhere like Advanced Circuits - you can get boards for pretty cheap. If I were you I'd build things up first on a breadboard, do all your testing and debugging, and then, ONLY then, think about a PCB.

As far as classes go, you'd probably need a couple; with something like Circuits or Circuit Analysis you can learn how to analyze circuits - that's the fundamental background you'll need. Then you'd need Electronics Circuits or something like that to learn different topologies, ways of putting components together to make useful circuits (that you can then analyze with techniques learned in the previous class). Of course, you can learn almost as much about that from building up and tinkering with predesigned circuits; classes mean a lot more once you have some practical background, too. You have some foresight into how important different concepts are and how to apply them, which makes learning the material much more interesting and consequentially easier.

 

[wrongwaydownup]

what you want is to go to http://dorkbot.org/ and find your closest local group and go to meetings and make friends there

 

[wrongwaydownup]

then go to makezine.com and hackaday.com and arduino.cc

 

[Super Nade]

Try this link (and other threads in that section), I'm adding resources all the time-->
http://www.ocforums.com/showthread.php?t=555890